Avid cyclists enjoy participating in full day, overnight, and even cross country tours of several days duration. For these longer rides more gear is required. A small volume of gear may be carried behind a bicycle seat. More gear must be carried in a back pack. It is more convenient and less burdensome to carry this additional gear in a bicycle trailer.
Like a good bicycle, a good bicycle trailer should be adequately strong and as light as possible. It should also be easily attached to, and removed from a bicycle. It is desirable if the bicycle can be laid down while remaining attached to the trailer. Most of the time the trailer is not in use. If the trailer is collapsible for storage, shipping and transportation it is much more convenient to keep and use.